Climate change will harm people from all nations. But one segment of humanity is on the front lines: the poor.

From the increased frequency of mega-storms like the one that devastated the Philippines in 2013 to rising seas displacing people of low-lying nations such as Bangladesh, it is the poor who will lose their homes first and suffer the gravest misfortunes.

The same is true here in the Bay Area. Both extreme weather events and sea levels rise will hit lower income communities in “the flats” with shoreline flooding — communities such as Richmond, Marin City, East Palo Alto, Alviso and Oakland.

But we can act now to buffer these communities with a green defense.

Tidal marshes are one of our greatest allies in making the Bay Area and our low-elevation communities more resilient to climate change. These marshes provide green spaces, wildlife habitat and a wide range of benefits to people such as water purification. They provide a buffer, a line of defense, from storm surges and rising seas. They knock down large waves and absorb floodwaters.

Unfortunately, most of our bay marshes have disappeared over the past two centuries. The flow of nourishing sediment that once allowed them to grow and build up over time has greatly diminished. We must reverse this course.

A new report released last week makes the case. “The Baylands and Climate Change: What We Can Do,” combines the research of more than 200 Bay Area scientists and government experts. Read the report at www.baylandsgoals.org.

The report presents the latest science and findings on the health and future of the bay’s shore. It then suggests a science-based roadmap to protect our communities.

That roadmap must include more wetlands. A 1999 science collaboration set a goal to restore and conserve 100,000 acres of San Francisco Bay tidal marsh. Today, we have conserved, restored or acquired approximately 72,000 acres.

We must accelerate this effort to restore the natural processes that allow marshes to grow to keep pace with sea level rise. We can achieve this by restoring our region’s stream flows and their connections to bay wetlands. This allows more sediment to nourish our marshes.

Another source of sediment is the material we currently dredge from shipping and flood control channels. We should be creative, and make it a priority to ensure all sources of sediment are used to grow our wetlands.

The time is now. An accelerated effort could save more than 80 percent of our existing tidal marshes over the next 100 years. The science shows that marshes established by 2030 are more likely to flourish and survive when sea level rise accelerates in the middle of this century.

Everyone in the Bay Area, even those living upland, has a stake in this effort. Crucial infrastructure that supports our daily lives, from water treatment plants to highways to San Francisco International Airport, are located along our bayshores in the path of rising seas.

Yes, we may need some so-called hard infrastructure, like levees and sea walls. But first, let’s change how we manage our landscapes and bayshores to promote wetland growth and regeneration. It is a grave injustice that residents of lower-income communities, with far lower carbon emissions per capita than wealthy enclaves, may suffer the most.

We can work with nature, not against it. The legislature should adopt climate action policies that give priority to protecting our most vulnerable, disadvantaged communities from rising tides. These actions will ultimately benefit the entire seven million residents of the Bay Area.

Assemblyman Tony Thurmond (D- Richmond) represents the 15th District, including shoreline communities such as Emeryville, Richmond and Hercules. He wrote this for this newspaper.

In closed door talks, Sen. Dianne Feinstein agreed to a major new water policy for California that sells out the Delta and guts Endangered Species Act protections. Sen. Barbara Boxer is fighting the good fight to remove the rider from her comprehensive water infrastructure bill, but it may take a presidential veto.